Metabolic consequences of hypercapnia in the rainbow trout, Salmo gairdneri: beta-adrenergic effects

The metabolic consequences of external hypercapnia (1% CO2) were assessed in rainbow trout (Salmo gairdneri) in the presence or absence of circulating levels of the beta adrenoceptor antagonist, propranolol. External hypercapnia caused a severe extracellular respiratory acidosis and a less pronounced reduction of hepatic intracellular pH (pHi). pHi was restored to prehypercapnic values after 48 hr of continuous hypercapnia due to elevation of bicarbonate levels. In the presence of propranolol, hypercapnia elicited a pronounced activation of pyruvate kinase (PyK) (measured at both low and high phosphoenolpyruvate (PEP) concentrations) and inactivation of both total glycogen phosphorylase (GPase) and glycogen phosphorylase a (GPase a). In the absence of propranolol, the changes in enzyme activities were significantly reduced (low PEP PyK activity) or totally absent (GPase inactivation). These results suggest that beta adrenoceptor-mediated phenomena offset disruptive effects of hypercapnia on PyK and GPase activities and may be important in the control of gluconeogenesis and glycogenolysis during this acid-base disturbance. The adrenergic effects were not related to modification of hepatic intracellular acid-base status. Hypercapnia induced a rapid depletion of liver glycogen and concomitant hyperglycemia. These effects were not prevented by pretreating fish with propranolol and appeared to be unrelated to changes in GPase a activity. These results suggest that factors other than adrenergic activation of GPase a are involved in the enhancement of liver glycogenolysis.     

Transoesophageal echocardiography in heart disease—old technologies, new tricks

Cardiac ultrasound and upper gastrointestinal endoscopy are relatively old technologies. With the introduction of new ultrasound probes and by incorporating ultrasound technology into conventional endoscopes, ‘new tricks’ in cardiac imaging were discovered. Posterior structures of the heart are now able to be imaged clearly by the ultrasound probe from the oesophagus. Consequently, better resolution of cardiac anatomy allows more accurate diagnosis of cardiac pathologies which is not possible using conventional transthoracic (TT) approach. Over a period of two years, 1200 cases of transoesophageal echocardiography (TOE) were undertaken in our institution. The major indications were diseases of the aorta (10%), source of cardioembolism (28%), assessment of native and prosthetic valve function (20%), suspected endocarditis and its complication (17%), pre and post percutaneous transluminal mitral valvotomy (PTMV [13%], congenital heart disease (2%) and others (10%). The greatest impact with TOE is in the diagnosis of aortic dissection and transection, TOE is superior to conventional TT approach in detecting potential source of embolism, valvular vegetations and its complication, native and prosthetic valve dysfunction and LA thrombus prior to PTMV. Observations by TOE such as spontaneous echo contrast (SEC) in the left atrium open new challenges for further research in its role in the pathogenesis of LA thrombus and its association with cardioembolic event. Other areas of interest include; reclassification of distal aortic dissection and the use of TOE in intra-operative work.     

Giant right atrial diverticulum: an unusual cause of Wolff-Parkinson-White syndrome.

A case of a giant right atrial diverticulum associated with neonatal supraventricular tachycardia is reported. The electrocardiogram in sinus rhythm showed pre-excitation that may have been caused by the right atrial diverticulum adhering to the right ventricle.     

Death certification and coding for ischaemic heart disease in Tasmania

Official records show that the rates of mortality from ischaemic heart disease (IHD) in Tasmania have been the highest of all the Australian states for most of the past decade. This study assesses the accuracy of the official Tasmanian mortality data for IHD in 1987 and 1988 for males aged 25 to 74 years using routinely available clinical and pathological data supplemented by information from the attending doctor. Our findings show that a death officially coded to ICD 9 rubrics 410–414 (IHD) in Tasmania has 94% sensitivity and a positive predictive value of 90% for fatal definite acute myocardial infarction or possible coronary death as defined by the WHO. Comparison of our results with those of two earlier studies undertaken in Australian mainland centres indicates that differences in the official statistics for coronary mortality between Tasmania and the mainland states reflect true differences in the risk of coronary death. While the results from three Australian studies suggest that the routine system of death certification is reasonably accurate, careful monitoring of death certification and coding practices need to be undertaken regularly in all states of Australia if secular changes in regional patterns of coronary mortality are to be regarded as credible. (Aust NZ J Med 1992; 22: 114–118.)     

Symptoms of pancreatic cancer

We describe the symptoms, physical findings, treatment interventions, risk factors, and length of survival in persons with pancreatic cancer referred to a palliative care service (PCS) in a tertiary care facility. Data were collected prospectively over a 2-yr period using a standard clinical assessment tool in 39 patients with unresectable pancreatic cancer. Common symptoms include pain (82%), anorexia (64%), early satiety (62%), xerostomia and sleep problems (both 54%), and weight loss (51%). Analyzed retrospectively, 82% had at least one known risk factor for the development of pancreatic cancer. Twenty-five people presented to the PCS within 1 mo of diagnosis; in this group, length of survival was analyzed according to the presence of specific symptoms, and a significant inverse relationship between the presence of dyspnea and length of survival was found. As there is no effective treatment for surgically unresectable pancreatic cancer, palliation of common symptoms should be the primary emphasis of therapy.     

adaptive fourier threshold filtering: A method to reduce noise and incoherent artifacts in high resolution cardiac images

We introduce an image processing method which reduces white noise and random artifacts in sets of high resolution, time resolved images. At each pixel, the processing consists of: (1) the isolation of a time intensity curve (TIC), (2) Fourier transformation of each TIC, (3) application of a threshold to remove low intensity coefficients, (4) inverse transformation to generate noise reduced TICS which are recombined to form images with improved signal-to-noise ratio (SNR). Noise filtering by Fourier thresholding is demonstrated on a set of cardiac images, resulting in a reduction of the noise energy by approximately 90%.     

Interleukin-1-inhibitor activity induced by respiratory syncytial virus: abrogation of virus-specific and alternate human lymphocyte proliferative responses

Respiratory syncytial virus (RSV) infection has been shown to induce human mononuclear leukocyte (MNL) production of net interleukin-1 (IL-1)-inhibitor activity. In the current studies of IL-1-inhibitor effects, RSV-exposed cells were compared with autologous MNL that were sham-exposed or exposed to inactivated RSV or influenza virus (which induces net IL-1 activity and commonly elicits effective homotypic immunity). Exposure of MNL to influenza virus or inactivated RSV resulted in increased expression of human leukocyte antigen-DR, the IL-2 receptor, and the transferrin receptor and increased progression through the cell cycle by 3 days. In contrast, exposure to infectious RSV resulted in decreased marker expression and cell cycle arrest, with abrogation of proliferation in response to the virus or other stimuli. These data raise the possibility that a contributing mechanism for recurrence of RSV infection is early suppression of the clonal expansion of virus-specific lymphocytes due to net IL-1-inhibitor activity.